Just like the Chinese boy who scratched his name on an ancient Egyptian temple wall, people have been leaving graffiti on Egyptian monuments for quite some time now.
In the early 6th century BC, some Greek and Carian mercenaries traveling up the Nile River in the service of the Pharaoh Psammetichus II left a long "Kilroy Was Here" memo scratched on one of the legs of the statue of Ramses II at his Abu Simbel funerary monument. Several Greeks and Romans of later times left graffiti on one of the Luxor statues of the Pharaoh Amenophis III. These constitute only a few of the most famous instances of such "defacements."
These ancient defacings of still more ancient Egyptian monuments now constitute some of our most valuable archaeological treasures.
Maybe, then — without giving the Chinese tourist a pass — perhaps we should give him a moment's respite; in another 2,000 or 3,000 years, he may be more famous than infamous.